Conventionally, the manufacture of ophthalmic compensation lenses requires on the one hand ophthalmic measurements to determine in particular the ocular refraction characteristics of the eyes of a person and on the other hand complementary measurements, especially of geometrico-morphological parameters of the wearer. These various measurements are required to manufacture and fit adequate ophthalmic lenses in the chosen frame and to adjust the spectacles to the sight and morphology of the wearer.
During an oculo-visual examination, an ophthalmologist or an optometrist carries out optometric measurements to evaluate the visual acuity of a person. The ophthalmic measurements may be obtained by various optometric apparatuses, in particular a refractometer for ocular refraction measurements. In the case where a person has a visual acuity defect, the result of an oculo-visual examination is often a prescription for ophthalmic lenses. This prescription generally indicates the refraction correction, often expressed by eye-lens distance, addition, axis and spherical, cylindrical or prismatic power characteristics, etc., required for the manufacture of adequate ophthalmic compensation lenses for each eye of the wearer.
An optometrist or an endorsed professional salesperson such as a dispensing optician effects the distribution, the fitting of the ophthalmic lenses in a spectacle frame and the adjustment of the lenses to the wearer.
For this purpose, the optometrist or the optician carries out a set of complementary optometric measurements relating to a person. The choice of a frame determines the physical dimensions of the lenses. The conditions of use of the spectacles, such as for example in near, far and/or intermediate vision, lead to the choice of parameters for the ophthalmic lenses from a single-vision, multifocal or progressive lens. In addition, various options allow the type and the quality of the ophthalmic lens to be chosen: mineral or organic material, surface (for example antireflection) treatment, photochromic glass, price range, etc.
The optician also determines the geometrico-morphological properties of the wearer, in particular the inter-pupillary distances or even the height of the focal point(s) relative to the lower edge of the frame. Various optometric apparatuses may be used to obtain the optometric measurements relating to the geometrico-morphological properties of the wearer, such as an autorefractometer, a photorefractive apparatus or a measuring column or tablet. Preferably, the optometric apparatuses allow measurements to be obtained in a natural posture that is ergonomic for the wearer and under well determined visual conditions. Advantageously, certain apparatuses allow optometric measurements in a plurality of habitual postures of the wearer corresponding for example to near, far and/or intermediate vision.
In the present document, the expression “optometric measurement” is understood to mean a measurement relating to one or more ophthalmic, in particular ocular refraction, parameters of a wearer, and/or to one or more geometrico-morphological properties of the wearer, in particular inter-pupillary distances or even the height of the visual axes relative to the edge of a frame, the measurement of pantoscopic angles, of eye-glass distance (EGD), of the position of the eye rotation center (ERC), of the face form angle of the frame, or even of behavioral parameters such as the eye-head coefficient, reading distance, the lowering of the gaze during reading, etc.
According to the laws in force in various countries, ophthalmic and geometrico-morphological optometric measurements may be carried out by the same qualified professional or in contrast must be carried out by various professionals each having reserved activities.
Together, the ophthalmic, geometrico-morphological or other optometric measurements allow the refraction of the lenses to be determined and the base curvature of the ophthalmic lenses to be calculated. The precision of the measurements of these geometrico-morphological parameters of the wearer is essential to ensure the ophthalmic compensation lenses once fitted into spectacles are centered relative to the visual axes of the wearer.
The optometrist or optician then validates the initiation of the manufacturing sequence of the ophthalmic spectacle lenses by a manufacturer. After reception of the adequate ophthalmic lenses, the optician fits the ophthalmic lenses into the spectacle frame chosen by the wearer and adjust the spectacles on the face of the wearer.
However, it has been observed that the precision of optometric measurements varies depending on the instruments used, the care taken with the measurements and depending on the respective professional qualifications of the optometrists, opticians or other authorized professionals involved in the various steps. However, the measurement results are generally not transmitted with a margin of error.
In addition, certain optometric measurements or geometrico-morphological parameters do not correspond to a uniform definition. For example, the pantoscopic angle of a lens represents the angle that the general plane of a lens makes relative to the vertical when worn. However, the sign convention of the pantoscopic angle may vary depending on the apparatus or the measurement center. A given pantoscopic angle may thus be evaluated as +8 degrees or −8 degrees. Such measurement differences are thus a source of errors.
Errors in the optical refraction parameters of the ophthalmic lenses, in the geometrico-morphological parameters, in the centering or adjustment of ophthalmic compensation lenses may, in certain cases, generate ocular complications for the wearer, visual discomfort, headaches or nausea and more generally lead to the wearer being unsatisfied with their spectacles.
Furthermore, there is a need for traceability of the optometric measurements in order to allow the quality of the ophthalmic lenses intended for a spectacle wearer to be adapted.
Document US2013/231941 describes an automatic system for distributing ophthalmic spectacles that allows from an image of the patient certain facial measurements to be determined. Document EP 2 466 540 describes a system for supervising and maintaining medical instruments remotely.